package com.dragon.trie;

import java.util.TreeMap;

/**
 * @author dragon
 * @version V1.0.0-RELEASE
 * @date 2019/5/25 10:25
 */
public class MapSum {

    private class Node {

        int value;
        TreeMap<Character, Node> next;

        public Node(int value) {
            this.value = value;
            next = new TreeMap<>();
        }

        public Node() {
            this(0);
        }
    }

    private Node root;

    public MapSum() {
        root = new Node();
    }

    public void insert(String word, int val) {
        if (word == null || word.length() == 0) {
            throw new IllegalArgumentException("添加的元素不能为空");
        }
        Node cur = root;
        for (int i = 0; i < word.length(); i++) {
            char c = word.charAt(i);
            if (cur.next.get(c) == null) {
                cur.next.put(c, new Node());
            }
            cur = cur.next.get(c);
        }
        cur.value = val;
    }

    public int sum(String prefix) {
        if (prefix == null || prefix.length() == 0) {
            throw new IllegalArgumentException("添加的元素不能为空");
        }
        Node cur = root;
        for (int i = 0; i < prefix.length(); i++) {
            char c = prefix.charAt(i);
            if (cur.next.get(c) == null) {
                return 0;
            }
            cur = cur.next.get(c);
        }

        return sum(cur);
    }

    private int sum(Node node) {
        int value = node.value;

        for (char c : node.next.keySet()) {
            value += sum(node.next.get(c));
        }

        return value;
    }
}
